The use of tape tab fastener systems for securing the corners of disposable absorbent articles such as diapers or incontinents briefs is well known in the art. Examples of adhesive tape tab fastener systems are disclosed in U.S. Pat. No. RE 26,151, U.S. Pat. No.3,848,594 and many other publications. While adhesive tape tab fastener systems did provide secure means for fixing a disposable absorbent article around a user's waist during use they were not totally satisfactory.
Adhesive tape tab fastener systems were often only usable upon initial fixation of the disposable absorbent article while refastening was not possible. They also displayed unsatisfactory resistance against contamination.
Hence the prior art discloses many alternative fastener systems trying to solve these problems. For example mechanical fastener systems of the hook/loop type (random entanglement) have been contemplated and disclosed in many publications. In general mechanical fastener systems have the advantage of reduced or no sensitivity versus contamination for example by oils or powders. Mechanical hook/loop fastener systems also have the advantage of being reclosable after opening for example to check the soiling of absorbent articles or to correct the fitting of absorbent articles on the wearer. However, mechanical fasteners require a two part fastening system e.g. tape tabs with hooks and a landing surface with loops.
Mechanical tape tab fasteners of the hook/loop type have been disclosed for use in diapers for example in U.S. Pat. No. 3,110,312 and for disposable diapers in U.S. Pat. No. 4,259,957 or European Patent Application EP-A-235014.
After establishing the principal advantages of mechanical fasteners over adhesive tape tab fasteners, it was found that mechanical fasteners lack the ease of disposability which the adhesive tape tab fasteners provided for disposable absorbent articles. Before disposing a used disposable absorbent article the article is often rolled up upon itself. This pack is then closed by applying the adhesive tape tab onto the outside surface of the rolled up disposable absorbent article.
The advantage of disposability is supplied by adhesive tape tabs which can be attached anywhere to the disposable absorbent article. Mechanical hook/loop fasteners by design require their respective counter surface to achieve an attachment. However, when rolling a disposable diaper onto itself one of the two mechanical fastening members, usually the landing member, is inside the roll and hence unaccessable.
Attempts to resolve this disposability problem have resulted in tape tab fastener systems combining mechanical and adhesive parts. Disclosure of such adhesive-mechanical tape tab fastener systems can be found for example in European Patent Applications EP-A-321232 or EP-A-324578. Adhesive-mechanical fastener systems have the combined advantages of low sensitivity versus contamination and exceptionally good reclosure performance as well as easy disposal of the absorbent article after use. However they still exhibit certain problems which only now have been defined and which are solved by the present invention.
Most adhesive-mechanical tape tab fasteners are in principle made like regular adhesive tape tab fasteners but include a mechanical fastener member on the adhesive tape surface. The adhesive of the tape is used to join the mechanical fastener member to the adhesive-mechanical tape tab fastener. In the process of making a disposable absorbent article the adhesive mechanical tape tab fastener is usually folded inwards into a so called packaging or transport position. In this position the adhesive member of the tape tab fastener requires a countersurface which would easily release the adhesive tape when the article is used. Usually, the countersurface is provided by placing a single sided adhesive tape, called release tape, in the respective release area. The adhesive side of the release tape provides its foundation and the non-adhesive reverse side provides the release function for the adhesive part of the tape tab fastener.
In European Patent Application 89201611.4 and 90202696.2 packages containing flexible articles such as disposable diapers have been disclosed in which the diapers are under up to 60% compression. These compression packages have since then become widely used, particularly since they reduce packaged volume and packaging material consumption while containing the same number of diapers as the historically used uncompressed packages. During packing very high pressures have to be exerted on the disposable absorbent articles to achieve the volume reduction necessary for making compression packages.
When having been packed into compression packages disposable absorbent articles with adhesive-mechanical tape tab fastener systems of the designs disclosed in the prior art often exhibit the problem of reduced mechanical fastening performance. It is believed that for diapers with mechanical fastening members comprising protruding elements like hooks or loops, this problem is due to the bending, weakening or destruction of at least some of the hooks or loops during compression.
It has now been found that the complex fastener system with release tape causes problems for the mechanical member integrity in conjunction with compressed packaging when the release tape and the mechanical fastening member have co-extensive areas in a transport position. If on the other hand this is prevented and the release tape is co-extensive with or smaller than the adhesive fastening member, problems of full or partial release tape detachment from the material to which the release tape is adhered have been exhibited. If the adhesion of the release tape to the underlying material is strong enough the underlying material may even be damaged thereby rendering the absorbent article useless. Both of these problems, which are calling for contradicting solutions, are solved and addressed by the current invention.
An objective of the present invention is to provide adhesive-mechanical tape tab fasteners for disposable absorbent articles which maintain the mechanical fastener member's integrity during manufacturing and packaging, in particular for disposable absorbent articles which are compression packed.
Another objective of the present invention is to provide an optimised fastening system having a reduced release tape length and a delamination introducing area to protect the release tape from becoming detached.
Another objective of the present invention is to provide an adhesive-mechanical tape tab fastener system having the afore-mentioned advantage at no increase or even at reduced material consumption to satisfy regulatory and user demands for ecological and economical fastening systems for disposable absorbent articles.
These and other objectives of the present invention will be more readily apparent from the following description and the accompanying drawings.